diff options
Diffstat (limited to 'tools/perf/util/cpumap.c')
-rw-r--r-- | tools/perf/util/cpumap.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c new file mode 100644 index 00000000000..4e01490e51e --- /dev/null +++ b/tools/perf/util/cpumap.c @@ -0,0 +1,59 @@ +#include "util.h" +#include "../perf.h" +#include "cpumap.h" +#include <assert.h> +#include <stdio.h> + +int cpumap[MAX_NR_CPUS]; + +static int default_cpu_map(void) +{ + int nr_cpus, i; + + nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); + assert(nr_cpus <= MAX_NR_CPUS); + assert((int)nr_cpus >= 0); + + for (i = 0; i < nr_cpus; ++i) + cpumap[i] = i; + + return nr_cpus; +} + +int read_cpu_map(void) +{ + FILE *onlnf; + int nr_cpus = 0; + int n, cpu, prev; + char sep; + + onlnf = fopen("/sys/devices/system/cpu/online", "r"); + if (!onlnf) + return default_cpu_map(); + + sep = 0; + prev = -1; + for (;;) { + n = fscanf(onlnf, "%u%c", &cpu, &sep); + if (n <= 0) + break; + if (prev >= 0) { + assert(nr_cpus + cpu - prev - 1 < MAX_NR_CPUS); + while (++prev < cpu) + cpumap[nr_cpus++] = prev; + } + assert (nr_cpus < MAX_NR_CPUS); + cpumap[nr_cpus++] = cpu; + if (n == 2 && sep == '-') + prev = cpu; + else + prev = -1; + if (n == 1 || sep == '\n') + break; + } + fclose(onlnf); + if (nr_cpus > 0) + return nr_cpus; + + return default_cpu_map(); +} |